Safety device for power punch presses



Aug. 21, 1928.

J. E. PAPAS SAFETY DEVICE FOR POWER PUNCH PRESSES Filed Jan. 30, 1925 2 Sheets-Sheet 1 lite-mung Aug. 21, 1928. 1,681,646

J. E. PAPAS I SAFETY DEVICE FOR POWER PUNCH PRESSES Filed Jan. 50, 1925 2 Sheets-Sheet 2 an, z f wi /L).

Elm M14 Patented Aug. at, 1928.

stares JOHN ELIAS PAPAS, OF CHICAGO, ILLINOIS.

SAFETY DEVICE FOR POWER PUNCH PR ESSES.

Application filed January so, 1925. Serial No. 5,715.

This invention is in the way of a safetydevice for power punch presses and its Ob]ect is to provide a simple, efiicient and practical device of this kind in which means are pro vided to prevent repeated operations while holding down the foot lever or treadle of the press.

Another object is to provide a modified device which will necessitate the press operator to take his hands from underneath the press to depress the treadle.

These and'other objects will be apparent from the accompanying drawings and specification.

In the drawings Fig. 1 is a side elevation of the device as mounted in connection with the clutch;

Fig. 2 is an end elevation of the device as mounted in connection with the clutch and fly wheel;

Fig. 3 is a cross section thru thebrake;

Fig. 4 is a modified form of a device built in connection with a standard toot lever and cable.

Figure 5 is a sectional view of part of the drum and flywheel showing the action of the clutch pin.

Figure 6 is a detail view of the hook level in operative position for engaging the extended end of the pin on the trip operating lever, other parts being removed.

Figure 7 is a detail view of the hook lever and associated parts with the hook lever in operative position and the treadle partially depressed.

This invention is carried out in combination with a form of clutch mechanism comprising a drum 1 having a collar 2 incorporated therein, in such a manner as toform a groove 3. A spring set clutch pin 4 which is adapted to engage the hub of the fly wheel 5 is mounted thru the collar 2 and the drum 1. The said clutch pin 4 is recessed to permit a dog 6 to engage the same. The invention proper consists in securing a lug 7 to the collar 2 and a block casting 8 to the side of the press. A trippcr arm 10 having an angular offset 11 and a hooked end 12 formed therein, is slidingly mounted in the end 9 of the cast ing 8. The lower end 13 oi the trippcr arm 10 is equipped with a pin 14 which rides in a slot 15 cut in the lower portion of the end 9 of the casting 8. A coil spring 16 connects the end 13 of the trippcr arm 10 with the upper portion of the end 9 of the casting 8.

A rocker arm 17 is pivotally mounted at one end 18 to the casting 8 and a trip operating lever 20 is slidingly passed thru the casting 8. The said trip operating lever 20 is preferably made of round stock with an eye formed in one end and a V-shaped groove 22 out in the opposite .end. A stem 23 having a coil spring 24 mounted thereon and carrying a dog 6 at its upper'end is mounted thru the casting 8 and pivotally secured with its lower end to the rocker arm 17 by means of links 25-. The trip operating lever 20 is pivoted to the rocker arm 17 as by a pin 19, one end of said pin 19 being extended outwardly of said rocker arm for a purpose hereinafter described. A brake box 28 having a spring aperture 29 and boltaperture 30 provided therein, is incorporated in the block casting 8. Adjustment blocks 31 and 32 which are adapted to engage a brake block 35 are provided. The adjustment block 31 is provided with a bolt aperture and spring seat 33, while the block 32 is provided with a threaded aperture 34-. A threaded bolt 36 having a hand wheel 37 secured thereto, and a coil spring 38 mounted thereon, is adapted to engage the bolt aperture 33 of the block 31 and the threaded aperture 34 of the block 32; the coil spring 38 passing thru the spring aperture 29 of the brake box 28 and seating against the spring seat incorporated in the bolt aperture 33. A portion of the ordinary foot lever or treadle cable 39 is shown fastened to the tripper arm and a conventional foot lever 70 is shown for the pun poses of illustration, other parts incidental to the support of the foot lever being removed.

In operation the spring 16 keeps the hooked end 12 of the tripper arm 10 in line with and above the groove 22 of the trip operating lever 20, so that when the foot lever or treadle is depressed, which causes the trippcr arm 10 to depress, the hooked end 12 of the said trippcr arm 10 engages the groove 22 of the trip operating lever 20 and depresses the same, which in turn depresses the stem 23 and compressesthe spring 24. Thus the dog 6 is disengaged from the clutch pin 4 of the clutch drum 1 permitting the said clutch pin 4: to engage the fly wheel 5. After a partial revolution of the clutch drum 1 the lug Y bears against the angular ottset 11 of the trippcr arm 10 and pushes the hooked end 12 out of engagement with the groove 22 of the trip operating lever'20 which permits the spring 24 to expand and return the dog 6 and the trip operating lever 20 to their norlnal positions. Thus the press is permitted to make but one revolution until the foot lever is released and the tripper arm 10 returned to its normal position by the spring 16, whereupon another operation can be obtained. If it is desired to obtain more than one operation of the press by a single depression of the foot lever, the operator moves the tripper arm 10 outwardly of the casting 8 in any convenient manner, as, for example, with his hand, and a pin (not shown) is inserted into the aperture 40 between the tripper arm 10 and the casting 8 in order to prevent the lug 7 from engaging the angular ofiset 11 when the clutch drum 1 rotates. A hook lever 26 is rotatably mounted on the lower end of the tripper arm 10 at a point directly below the aforesaid pin 19 as by a. pin 66. A hook 67 is provided at one end of said hook lever, and a handle 68 is provided oppositely the hook. That side of the hook lever facing the hook is adapted to act as a cam as at 69 to engage the pin 19 when the said'hook lever is rotated by the operator in any convenient manner, as for example, by the operators hand; the hook 67 is positioned outwardly the said pin 66 a greater distance than the distance between the pin 19 and said pin 66 when the parts are in the position shown in Figure 1, and the cam 69 isadapted to prevent the alignment of the said hook with the pin 19 until the pin 66 is moved downwardly a slight distance from said pin 19, as by pulling down the tripper arm 10 by the cable 39 and foot lever 70; the operator continues to urge the rotation of the said hook lever while such movement is taking place, whereupon the cam 69 is adaptedto permit the hook 67 to engage the pin 19. Further movement of the tripper arm 10 by depressing the foot lever 70 will now, by reason ofthe engagement of said hook lever with said pin 19, cause the movement of the rocker arm 17 and'thus (lisengage the dog 6 from the clutch pin 4 so as to permit the press to operate-as long as the foot lever 70 is depressed. As soon, however, as the foot lever is released, the action of the spring 16 will urge the tripper arm 10 upwardly relatively to the rocker arm 17, so as to cause the pin 66 to approach the pin 19, whereupon the cam 69 will cause the hook 67 to be positioned out of alignment with said pin 19, as heretofore described, so that the operator is required to again urge the rot-ation of the hook lever about the pin 66 in order to operate the press by depressing the foot lever. As shown in Figure 1, the aforesaid described movement of the pin 66 relative to the pin 19 can not take' place while the hooked end 12 of the tripper arm 10 engages the groove 22 of the trip operating lever 20, so it is necessary that the said tripper arm 10 be moved outwardly the casting 8 in order that the hooked end 12 may clear the trip operating lever 20 aforesaid. So long as a pin (not shown) is positioned in the aperture 40 as described, the press will remain inoperative until the hook lever is urged into engagement with the-pin 19 while the foot lever is depressed, but if the pin is removed, and the hook lever urged into engagement with the pin 19 and the foot lever depressed, so as to cause the press to operate in the manner described, then, when the foot lever is released, all the parts will resume the position shown in Figure 1. It is sometimes necessary, in an emergency, to permit the press to make more than one revolution without releasing the foot lever 70, which the hook lever 26 isdesigned to permit being done; also, the provision of the aperture 40 permits the press to be rendered inoperative against accidental depression of the foot lever 70 when setting the work. The fact that, no matter what the setting of the parts may be, the hook lever 26 will be automatically thrown out of engagement with the in 19 upon releasing the foot lever 70, provi es :1 safety feature thought to be necessary in order to ensure the operation of the safety device as soon as the emergency has passed.

In the modified view shown-in Fig. 4 the device'comprises a plate 42 which is secured to the side ofthe press 41 by means of bolts 43. An arc-shaped flange 44 carrying lugs 45 and an arm 46 is incorporated in the plate 42. A hand lever 47' carrying a pin 48 which is adapted to engage one of the lugs 45 and the flange 44, is pivotally secured to the arms 46. A lever 49 carrying a shoe 50 which engages the arc-shaped flange 44 and the pin 48 is rigidly secured to a shaft 51 which is journaled in the plate 42. An arm 52 which is rigidly mounted upon the shaft 51 is secured to the tripper arm 56 of the clutch and the treadle cable 57 A guide 53 is bolted over the hand lever 47 to prevent depressing the same too much. A bracket 54 carrying a spring 55 which is secured to the hand lever 47, is secured to the press 41 above the guide 53. A

duplicate device is mounted on the opposite side of the press, so that when the operator desires to throw the clutch of the said press, he Will beforced to depress the hand levers 47 on both sides of theprcss in order to withdraw the pins 48 which protrude beyond the edge of the flanges 44. so as to permit the shoes 50. to clearthe said pins, when depressing the treadle 58 which turns the shaft 51 thru the medium of the arm 52 and trcadle cable 57.

In Figure 5 is shown the action of the clutch pin 4 and dog 6 in relationship to the flywheel 5, the embodiment shown being'one of the forms thereof well known to those skilled in the art andnot a part of this invention except as heretofore described, but it is obvious that any other similarly adaptable form may be used without departing from the spirit of my invention.

In the figure the reference character 59 refers to a cam face provided on the dog 6, the

said dog 6 being of an annular shape as shown in Figure 1 and slidably engaging the groove 3 aforesaid. The said cam face is positioned so as to engage with the lug formed on the pin 4 so as to provide thereby the recess 61 adapted to receive the said dog 6. In the flywheel 5 is provided the recess 62 adapted to receive the head 63 provided on the pin 4, the said head 63 being adapted to slidably engage the recess 64 in the said drum 1 the coil spring 65 is mounted on the pin 4 suitably to bear against the head 63 so as to normally force the said head 63 against the face of the hub of the flywheel 5 and to force the said head 63 into the recess 62 when the said recess is opposite to the recess 64, whereupon motion communicated to the flywheel 5 by any convenient means (not shown) will be communicated to the drum 1, thus causing the punch to act in a manner well known to those skilled in the art.

In Figure 5, the said head 63 is shown in the process of being disengaged from the recess 62 by reason of the cam face 59 engaging the lug 60, thereby causing the pin 4 to move inwardly and withdraw the head 63 into the recess 64, thus disengaging the drum 1 from the flywheel 5. In the embodiment shown, the flywheel 5 rotates continuously, during which rotation the head 63 slidably engages the face of the hub of the flywheel 5 as before described.

It is obvious that thelug 60 will join between the cam face 59 and the collar 2 unless means be provided for stopping the rotation of the drum 1, for which purpose is provided the brake block 35 and cooperating mechanism as heretofore described. I

When it is desired to have the drum 1 again rotated by the flywheel 5, the dog 6 is caused to be pulled down in a manner as heretofore described, whereupon the lug 60 being disengaged from the cam face 59, the spring 65 is free to cause the head 63 to engage the recess- 62 when the rotation of the flywheel 5 again brings the recess 62 opposite the rcoess64 as heretofore described.

While I have herein described a certain specific method of constructing and assembling the elements of my invention, it is un-' derstood same may be varied in minor details, not, departing from the spirit of my invention as defined in the appended claims.

I claim:

1. A safety dcvice for power punch presses, comprising the combination with a clutch mounted on a flywheel, a dog for disengaging said clutch from said flywheel and a dependent stem positioned on said dog, of a block arm for disengagin casting having a tripper arm slidingl mounted through one end; a rocker arm plvoted to the opposite side of the casting; a trip operating lever 'pivotally mounted on the rocker arm, slidingly mounted through the casting adapted to normally engage the tripper arm;

and a lug mounted on the clutch for disena trip operating lever pivotally mounted on the rocker arm, of automatically releasable means for rendering said safety devlce none operative, said means comprising a pm mounted thru the end of said rocker arm; and

.a hook lever pivoted to the lower end of the tripper arm for engaging the pin; whereby said tripper arm may be. locked to said rocker arm; means for disengaging said tripper arm from said trip operating lever; and means for automatically disen aging said hook lever from said pin wherefiy said tripper arm may engage saidtrip operating lever.

3. In combination with the clutch arrangement of a power punch press, comprising a clutch drum, a dog for'disengaging the clutch and a dependent stem on said dog, a safety device, comprising a block casting; a tripper arm having an angular offset and a hooked end formed therein slidingly mounted through one end of the casting; a rocker arm pivoted on the opposite end of the casting,

said stem being pivoted to said rocker arm; a

gaging the hooked end of the tripper arm; a

lug mounted on the clutch drum adapted to bear against the angular offset of the tripper the said hooked end from the groove of t 1e trip operating lever, whereby said disengaging of said hooked end from said trip operating lever will cause said dog to disengage said clutch; and means for returning the tripper arm to a normal position.

In testimony whereof I afiix my signature.

J OHN ELIAS PAPAS. 

